Which statement accurately reflects diagnostic criteria for preeclampsia related to timing and measurement?

• A. It is diagnosed in the first trimester with a single reading
• B. It requires persistent hypertension before 20 weeks
• C. It involves new onset hypertension after 20 weeks measured twice 4 hours apart in a patient without prior hypertension
• D. It is diagnosed based on edema alone

Answer: (C)

Preeclampsia diagnosis hinges on new hypertension that develops after 20 weeks of gestation and is confirmed by persistent elevation — two readings at least four hours apart in a patient with no prior hypertension. This timing and the requirement for two measurements reduce the chance of labeling a transient spike as disease. In real practice, you also look for proteinuria or other end-organ signs, but the timing and measurement pattern described are the essential match for the option.

Why the other ideas don’t fit: diagnosing in the first trimester with a single reading would misplace the condition and rely on one moment of high pressure, which isn’t how hypertension in pregnancy is confirmed. Persistent hypertension before 20 weeks points to chronic hypertension, not preeclampsia. Edema alone isn’t specific enough to diagnose preeclampsia, since swelling can occur in normal pregnancy and must be accompanied by high blood pressure and evidence of proteinuria or organ involvement.